One of the recurring problems with a body-worn device having transducers (e.g., acoustic sensors) is the accumulation of material that might block the proper operation of the transducer. Hearing assistance devices that are body worn and which have one or more transducers frequently encounter an accumulation of moisture, wax or other foreign material that can occlude apertures for the transducers and cause damage to the transducers eventually. One example of a hearing assistance device is a hearing aid. Hearing assistance devices often include on or more acoustic sensors, such as a microphone or receiver. These acoustic sensors are exposed to unwanted substances, such as wax, debris, moisture, or vapor. Hearing assistance devices may include a barrier layer arranged to reduce the amount of unwanted substances that can reach the acoustic sensor. However, occlusion and other effects of the buildup of wax, moisture and other materials continue to be an issue with such devices.
What is needed in the art is an improved method or apparatus for manufacturing barrier layers that meet requirements for acoustical transparency, resistance, repellency, and other characteristics. Such method and apparatus should not only improve the longevity of the transducers, but also provide reduced occurrences of partial or full blockage of apertures used for sound reception by hearing assistance devices. Such method and apparatus will allow less foreign material through to the transducer.